Install ARM Qt Cross Compiler on Debian 7 Wheezy

As I spent a lot of time trying to install ARM Qt Cross Compiler (for BeagleBone Black) on my Debian Wheezy, now I want to start installation from scratch, so please if anyone can give me some instructions, for example, what basic things I need to understand before I go into this? I tried several tutorials on how to install and configure arm cross compiler on my Debian distribution but without success. Thanks